The present invention relates to an imaging and recording apparatus for electrically recording optical images of a subject as image information signals, and in particular to an imaging and recording apparatus having enhanced manipulation performance when the apparatus is connected to a peripheral device and the image information signals are exchanged between the apparatus and the device.
As conventional apparatuses of this kind, there are so-called electronic cameras. Examples of the electronic cameras include a digital still camera described in Sasaki et al., xe2x80x9cPicture coding for digital still cameraxe2x80x9d, Journal of The Institute of Television Engineers of Japan, Vol. 46, No. 3, (1992), pp. 300-307 (hereafter referred to as conventional technique reference 1) and a camera of DS-100 type described in a catalog xe2x80x9cFUJIX DIGITAL STILL CAMERA SYSTEMxe2x80x9d published by Fuji Photo Film Co. Ltd. in September 1991 (hereafter referred to as conventional technique reference 2).
In electronic cameras described in the conventional technique references 1 and 2, image information signals derived by using an imaging device are digitized (quantized) and recorded in a card having a semiconductor memory thereon (hereafter referred to as memory card) as shown, for example, in FIG. 1 of the conventional technique reference 1.
In the conventional technique references 1 and 2, image information signals are thus handled as digital signals. Therefore, connection to peripheral devices such as personal computers originally handling only digital signals is easy (because signals can be transmitted and received as digital signals without the intervention of analog-digital converters and the like). Furthermore, the image quality degradation is not caused by the transmission line. Thus, the performance of connection with other systems is shown to be good.
In the conventional technique reference 1, concrete examples regarding the connection with peripheral devices are not described. However, it is considered that a memory card is used as an intermediate medium. In the conventional technique reference 2, an example of use of such a memory card is disclosed. That is to say, a memory card is first mounted on an electronic camera to record image information signals. Thereafter, this memory card is detached from the electronic camera and mounted on a peripheral device separate from the electronic camera. The image information signals recorded on the memory card are read out into this peripheral device. In this case as well, no methods are disclosed except the above described method using a memory card as the intermediate medium as the method for transmitting image information recorded in the memory by the electronic camera to the peripheral device in the form of digital signals as they are (with the intervention of neither a digital-analog converter nor an analog-digital converter).
As a known apparatus connected to a personal computer or the like to electrically transmit and receive image information signals, there is a still image compressing and expanding substrate of FSA 2001 type described in xe2x80x9cSummary of FSA 2001xe2x80x9d published by Fuji Film Microdevices Corporation on Jun. 24, 1991 (hereafter referred to as conventional technique reference 3). The apparatus described in this conventional technique reference 3 incorporates a semiconductor memory for storing digital image information signals. Between this apparatus and a personal computer connected thereto via a connector, a cable and the like, the digital image information signals are stored in the above described semiconductor memory or digital image information signals already stored are transmitted and received in the form of digital signals as they are.
Apparatuses of the conventional technique references 1 and 2 are camera apparatuses having imaging means for generating electrical image information signals from optical images. On the other hand, the apparatus of the conventional technique reference 3 has no such means and image information signals are generated by a personal computer. Image information signals generated by the personal computer are transmitted to the apparatus described in the conventional technique reference and stored temporarily in a first memory. Subsequently, the image information signals read out from the first memory are subjected to image data compression processing using the DCT (discrete cosine transform) method and resultant signals are sent back to the above described personal computer. Such an operation is similar to the operation of the apparatus block shown in FIG. 2 of the conventional technique reference 1.
Operation for writing or reading image information signals in the apparatus described in the conventional technique reference 3 is executed under time management of the connected personal computer. Otherwise, duplication of writing operation and reading operation of information data in the above described first memory may cause data of a certain image to be switched to data of a different image while the former cited data are being read out, resulting in deformed image information. Such a disadvantage can be prevented in the apparatus described in the conventional technique reference 3.
The apparatus described in the conventional technique reference 3 conducts processing for compressing the above described image data and outputs image information signals thus compressed. Data are outputted from this apparatus to the personal computer in synchronism with a clock outputted from the personal computer. However, image data compression is conducted by using an independent clock within this apparatus, i.e., a clock which is not in synchronism with the clock outputted from the personal computer. Therefore, the apparatus has a buffer memory of so-called FIFO (Fast In/Fast out) type.
Operation of this FIFO memory will now be described by referring to FIG. 2.
In FIG. 2, the FIFO memory 21 has data storage areas of memory address 0, 1, 2, . . . , n, n+1, m. Upon operation start of the memory 21, data are written into address 0, and then in the order of address 1, 2, . . . . The write address is updated every repetition timing of the above described clock within the apparatus. If data are written into the address n, data readout is started from the address 0 at this timing. In the same way as writing, data are then read in the order of address 1, 2, . . . . The read address is updated every repetition timing of an external clock supplied from the above described personal computer to the above described apparatus. Thereafter, the read address is also updated so as to follow the write address successively updated. As for both writing and reading, upon reaching address m, the address is so controlled as to return to address 0 at the next clock timing.
The FIFO memory is operated as heretofore described. It is now assumed that Aos (=n) is the address offset value of the initial state between writing and reading, whereas Axe2x80x2 os (=mxe2x88x92n) is the address offset value between writing and reading when the write address has reached the final address m of the buffer memory, and T is the repetition period of the above described read clock supplied from the outside. Even if the timing of the write clock is deviated from the generation timing of the read clock by at most Aosxc3x97T in the lag direction and by at most Axe2x80x2 osxc3x97T in the lead direction, data can be read out correctly in the order in which they have been written into the memory. That is to say, between systems activated by asynchronous clocks, data transfer can be executed in the correct order by providing a FIFO buffer memory between them.
In case a FIFO memory is used, however, the write clock (internal clock of the above described apparatus in case of compressed data output operation mode of the apparatus described in the conventional technique reference 3) and the read clock (the clock supplied from the personal computer to the above described apparatus in case of the compressed data output operation mode) cannot be established without mutual relation at all. As for the difference in repetition frequency between clocks, for example, the address offset value regulated from the capacity of the buffer memory in use becomes a restriction factor. Furthermore, the start timing of read operation must be subjected to-time management with respect to timing of write operation.
The apparatus described in the conventional technique reference 3 further has a function of inputting a compressed image information signal from the personal computer, restoring the original uncompressed image information signal in an internal data expansion circuit, storing the restored original uncompressed image information signal in the above described first semiconductor memory, and thereafter returning this restored image information signal to the personal computer. In such operation as well, operation timing of this apparatus is executed under management of the connected personal computer. Therefore, it is possible to prevent such a situation that writing, into the first semiconductor memory, an image information signal which has not been subjected to compression processing and which is supplied from the computer overlaps in time with writing the above described restored image information signal into the first semiconductor memory.
In such operation, the FIFO memory operates by using, as a write clock, the clock supplied from the personal computer and using, as a read clock, the internal clock of the apparatus. The interrelation between these two clocks is the same as that of the output operation of the above described compressed image information signal.
In the apparatus described in the conventional technique reference 3, the program of the personal computer connected for use is configured so as to prevent occurrence, in the FIFO memory, of such an operation mode that writing using the internal clock of the apparatus overlaps in time with writing using the clock supplied from the personal computer.
Electronic circuits for the imaging and recording apparatuses such as electronic cameras described in the conventional technique references 1 and 2 can be implemented in extremely small-sized circuit blocks by using recent high-integration LSI technique and high-density substrate mounting technique. Therefore, especially in fabricating a small-sized camera using a monofocus optical lens and a memory card as described in the above described conventional technique reference, the space for housing this memory card, the space for mounting a memory card loading connector, or the space of a mechanism for pulling out the memory card becomes a primary factor hindering the size reduction.
Furthermore, it is conceivable to reduce the size of the memory card as the size of the apparatus is reduced. However, pulling out a further smaller-sized memory card from a smaller-sized apparatus involves troublesome manipulation. There is also a fear that the apparatus will be inadvertently dropped in pulling out the memory card and the apparatus will be destroyed.
The above described disadvantage caused by pulling out and putting in the memory card can be dissolved by providing a connector for inputting and outputting image information signals in the imaging and recording apparatus and thereby sending/receiving signals directly to/from an external device via this connector. In the imaging and recording apparatus, however, there is provided a recording switch corresponding to the shutter button of a conventional film camera. There is a case where closing this recording switch causes execution of operation of taking in an optical image at an arbitrary timing which is desired by the operator and which is not restricted by the operation situation of an external device connected to the above described connector and recording the optical image in the semiconductor memory as an electric signal. Or there is a case where the execution is desired. For example, the case where an external device is put into the connector in such a state that the recording operation within the apparatus is not to yet been completed after the recording switch has been closed corresponds to the former case. The case where a picture is to be recorded without throwing away the chance of clicking the shutter at certain moment corresponds to the latter case. In case a connector as described above is provided in the imaging and recording apparatus, there is needed new operation management differing from the aforementioned apparatus described in the conventional technique reference 3, in which every apparatus operation is subjected to centralized management by a computer, in order to prevent deformation of image contents caused by overlap of information writing with information reading in the semiconductor memory or in order to avoid disadvantage of deformation of image contents resulting from competition in the same semiconductor memory between information writing caused by manipulation of the recording switch and information writing inputted from an external device.
Furthermore, a personal computer is conceivable as an external device for exchanging image information with the imaging and recording apparatus. In this case, however, it is extremely effective from the aspects of universality and manipulation capability to make possible information exchange by inputting an information transmission clock having no correlation at all with respect to the system operation clock used within the imaging and recording apparatus from the personal computer to the imaging and recording apparatus.
In view of the above described points, an object of the present invention is to provide a small-sized imaging and recording apparatus which is capable of preventing false operation and which is excellent in universality and manipulation capability.
The above described object is achieved by an imaging and recording apparatus having a semiconductor memory, apparatus operation start commanding means such as a recording switch, and control means for exercising control so as to write image information signals obtained by imaging into the semiconductor memory in response to an operation start command given by the apparatus operation start commanding means. In accordance with one feature of the present invention, the imaging and recording apparatus includes a first connector for outputting an image information signal stored in the semiconductor memory to the outside of the apparatus or for inputting a signal to be stored in the semiconductor memory to the inside of the apparatus, and state detection means for detecting a first state, i.e., an exchange ready state or exchange execution state of image information with respect to an external device and for detecting a second state, i.e., an operation state for writing an image information signal into the semiconductor memory in response to closure of the recording switch, by detecting the fact that the first connector has been inserted into a second connector provided in the external device or detecting a signal supplied from the external device via the first connector. When the state detection means has detected the above described first state, writing a new image information signal into a semiconductor memory in response to closure of the above described recording switch is inhibited. When the state detection means has detected the above described second state, transition to the state for executing exchange of image information with the external device is inhibited.
Furthermore, in an aspect preferred for improving the manipulation capability of an imaging and recording apparatus according to the present invention, a detection signal obtained when the above described second state has been detected is adapted to be outputted to the above described first connector.
Furthermore, in an aspect allowing various methods using an imaging and recording apparatus according to the present invention, terminals of the first connector are put out on an armoring side face of the apparatus looking toward a direction different from the incidence direction of a picture to be imaged.
The above described state detection means has a switch pressed and closed when the first connector has been inserted into the second connector, for example. This switch outputs an electric signal while these connectors are in the insertion state. Or after the insertion of the connector, a signal inputted from the external device via these connectors at least before execution of exchange of image signals with the external device is detected and an electric signal indicating the first state is outputted. However, while the semiconductor memory is in the write operation mode of image information signals in response to closure of the recording switch, i.e., while the semiconductor memory is in the second state, outputting the above described electric signal from the state detection means is inhibited. When there is an output electric signal indicating the first state of the state detection means, control is exercised so as to inhibit writing image information signals responsive to closure of the recording switch, in the semiconductor memory to be accessed for exchanging image information signals with the external device.
Even if the user should inadvertently manipulate the recording switch when image information is being exchanged with the external device, contents of images being exchanged are not deformed owing to the operation heretofore described according to the present invention. Furthermore, by providing a buffer memory for temporary storage in a stage preceding the semiconductor memory, for example, and inhibiting image information signals from the buffer memory to be written into the semiconductor memory as described above, picture imaging responsive to manipulation of the recording switch is possible even in the interval of operation of signal exchange with the external device.
When outputting the electric signal indicating the first state from the state detection means is inhibited, i.e., in the second state, the access state of the semiconductor memory selected to write the image information signal in response to closure of the recording switch is maintained and transition to a state allowing access from the external device is inhibited.
Even in the state in which a series of operations for recording the imaged picture are continued, the above described operation according to the present invention makes it possible to execute manipulation for connecting the external device without deforming contents of the picture.
Furthermore, if the semiconductor memory is configured so that an electric signal indicating that the semiconductor memory is in the second state is outputted from the state detection means and the electric signal is used as an apparatus output via the connector, it becomes possible to detect, in an external device connected via the connector, the end of the second state. Therefore, after the end of imaging and recording operation started at timing which is not under time management of the external device by the recording switch or operation start commanding means incorporated in the imaging and recording apparatus of the present invention including a receiving portion of a remote controller using infrared rays or the like, the semiconductor memory can be accessed from the external device immediately or automatically.
Furthermore, in an imaging and recording apparatus according to an aspect of the present invention, the first connector is put out in a direction different from the incidence direction of the optical image of the subject. Thereby, it becomes easy to keep the field of subject view of the imaging and recording apparatus in such a state that the first connector is surely coupled to the second connector possessed by an external device or the like.
Furthermore, in accordance with the present invention, writing an image information signal in response to the recording switch, which is the internal operation of the apparatus, and reading/writing an image information signal, which is the operation of exchanging information with an external device of the apparatus are executed independently in a time-division fashion. There are no temporal restraints imposed upon operation timing between divided operations. By supplying, from the outside of the apparatus, a clock having no correlation with the internal system operation clock of the apparatus, therefore, exchange of image information with the apparatus can be executed.